Survival, fusion, and hardware failure after surgery for spinal metastatic disease

Abstract

OBJECTIVEDecompression with instrumented fusion is commonly employed for spinal metastatic disease. Arthrodesis is typically sought despite limited knowledge of fusion outcomes, high procedural morbidity, and poor prognosis. This study aimed to describe survival, fusion, and hardware failure after decompression and fusion for spinal metastatic disease.METHODSThe authors retrospectively examined a prospectively collected, single-institution database of adult patients undergoing decompression and instrumented fusion for spinal metastases. Patients were followed clinically until death or loss to follow-up. Fusion was assessed using CT when performed for oncological surveillance at 6-month intervals through 24 months postoperatively. Estimated cumulative incidences for fusion and hardware failure accounted for the competing risk of death. Potential risk factors were analyzed with univariate Fine and Gray proportional subdistribution hazard models.RESULTSOne hundred sixty-four patients were identified. The mean age ± SD was 62.2 ± 10.8 years, 61.6% of patients were male, 98.8% received allograft and/or autograft, and 89.6% received postoperative radiotherapy. The Kaplan-Meier estimate of median survival was 11.0 months (IQR 3.5–37.8 months). The estimated cumulative incidences of any fusion and of complete fusion were 28.8% (95% CI 21.3%–36.7%) and 8.2% (95% CI 4.1%–13.9%). Of patients surviving 6 and 12 months, complete fusion was observed in 12.5% and 16.1%, respectively. The estimated cumulative incidence of hardware failure was 4.2% (95% CI 1.5–9.3%). Increasing age predicted hardware failure (HR 1.2, p = 0.003).CONCLUSIONSLow rates of complete fusion and hardware failure were observed due to the high competing risk of death. Further prospective, case-control studies incorporating nonfusion instrumentation techniques may be warranted.

Hardware Failure in Spinal Tumor Surgery: A Hallmark of Longer Survival?

“…Prior studies have found that increasing age, smoking, preoperative radiotherapy, constructs spanning 6, or more levels, and a prior chest wall resection were risk factors for instrumentation failure after spinal surgery for tumor [ 13 - 18 ]. In contrast, in our study those risk factors were increasing SMII, pelvic fixation, and longer survival of more than 5 years.…”

“…In contrast to prior studies, our results did not find that preoperative radiotherapy was a risk factor for hardware failure [ 18 ]. While osteoradionecrosis is a conceivable mechanism [ 31 ] for this this reported association [ 32 ], it was derived from a model with 7 covariates but only 3 failure events, creating a high likelihood of a small-sample bias and a model inaccuracy [ 13 ]. Moreover, 38% of patients in study of Pedreira et al [ 18 ] had a preoperative radiotherapy compared with only 6% in our patients.…”

Spinal metastasis: narrative reviews of the current evidence and treatment modalities

“…Bone quality of the metastatic vertebrae may be hindered by tumour invasion, systemic cancer treatment and poor nutritional status. 98 While the benefit of spinal fusion is robust in preventing hardware failure in degenerative spine surgery, its necessity is still debatable in the setting of spinal metastasis. 97 – 99 In metastatic patients, evidence suggests a low fusion rate at 1 year, with only 16.1% achieving complete fusion, after the surgery.…”

“… 98 While the benefit of spinal fusion is robust in preventing hardware failure in degenerative spine surgery, its necessity is still debatable in the setting of spinal metastasis. 97 – 99 In metastatic patients, evidence suggests a low fusion rate at 1 year, with only 16.1% achieving complete fusion, after the surgery. 98 The rate of spinal fusion over a longer time period may be difficult to evaluate due to the high mortality rate.…”

“… 97 – 99 In metastatic patients, evidence suggests a low fusion rate at 1 year, with only 16.1% achieving complete fusion, after the surgery. 98 The rate of spinal fusion over a longer time period may be difficult to evaluate due to the high mortality rate. The rate of hardware failure requiring reoperation is reported to be 4.2% at 1 year and 12.5% at 2 years.…”